1. Field of the Invention
This invention relates to flow testing of existing wells and more particularly to test tools which are run on a flexible line and are operable thereby from the surface to shut in a well and to open it up at a subsurface depth, preferably at a location just above the formation being tested, the test tool being installed in a landing nipple at or near the producing formation to be tested.
2. Description of the Prior Art
Until a few years ago, downhole well data were generally obtained by lowering a bottom hole pressure gage into a well on a wire line after the well had been closed in at the surface for maybe 48 to 72 hours. The gage usually carried a maximum-recording thermometer. The gage was lowered to a location a predetermined distance below sea level, usually at or near the casing perforations. The gage was normally suspended at this depth for a few minutes while the well remained shut-in to record the formation pressure and temperature. The well was then placed on production at a predetermined rate of flow to obtain recordings of the draw-down characteristics of the well. The data thus obtained were then evaluated by reservoir technicians to aid them in their effort to determine more accurately the extent, shape, volume, and contents of the reservoir.
Since the well was controlled by valves located at the surface, usually a great distance from the reservoir, problems arose as a result of the reaction of the column of production fluids in the well tubing. During shut-in periods, liquids would settle to bottom and the gas would collect thereabove, introducing uncertainties into the data obtained and clouding the formation's characteristics. It became desirable to have the ability to open and close the well at a point as near the perforations as possible and thus avoid the need to build up and draw down the great volume and height represented by the well bore or well tubing extending many thousands of feet from the reservoir to the surface. Further it was desirable to run a test tool including sensor means on a conductor cable and be able to control the downhole opening and closing means from the surface while recording and displaying at the surface, and in real time, the downhole data as they were sensed by the test tool.
The Applicant is familiar with the following prior patents which may have some bearing upon the well testing problems as relates to the present invention.
______________________________________ Re.31,313 4,051,897 4,286,661 2,673,614 4,134,452 4,373,583 2,698,056 4,149,593 4,487,261 2,920,704 4,159,643 4,583,592 3,208,531 4,274,485 ______________________________________
Also, Applicant is familiar with a brochure published by Flopetrol-Johnston covering their MUST Universal DST device.
Applicant is further familiar with an editorial comment published in WORLD OIL magazine, page 21, Oct. 1983 Edition.
In addition, they are familiar with the landing nipples illustrated on page 5972 of the Composite Catalog of Oil Field Equipment and Services, 1980-81 Edition, published by WORLD OIL magazine.
U.S. Pat. No. 4,134,452 issued to George F. Kingelin on Jan. 16, 1979; U.S. Pat. No. 4,149,593 issued to Imre I. Gazda, et al, on Apr. 17, 1979; U.S. Pat. No. 4,159,643 issued to Fred E. Watkins on July 3, 1979; U.S. Pat. No. 4,286,661 issued on Sept. 1, 1981 to Imre I. Gazda; U.S. Pat. No. 4,487,261 issued to Imre I. Gazda on Dec. 11, 1984; U.S. Pat. No. 4,583,592 issued to Imre I. Gazda and Phillip S. Sizer on Apr. 22, 1986; and U.S. Pat. Re. No. 31,313 issued July 19, 1983 to John V. Fredd and Phillip S. Sizer, on reissue of their original U.S, Pat. No. 4,274,485 which issued on June 23, 1981, all disclose test tools which may be run on a wire line or cable and used to open and close a well at a downhole location by pulling up or slacking off on the wire line or cable by which these test tools are lowered into the well. In most of the above cases, a receptacle device is first run on a wire line and anchored in a landing nipple, then a probe-like device is run and latched into the receptacle. In the other cases, the receptacle is run in with the well tubing.
U.S. Pat. No. 4,134,452 provides only a tiny flow passage therethrough openable and closable by tensioning and relaxing the conductor cable for equalizing pressures across the tool.
U.S. Pat. No. 4,149,593 is an improvement over the device of U.S. Pat. No. 4,134,452 and provides a much greater flow capacity as well as a locking sub which locks the tool in the receptacle with a tenacity somewhat proportional to the differential pressure acting thereacross.
U.S. Pat. No. 4,286,661 is a division of U.S. Pat. No. 4,149,593, just discussed, and discloses an equalizing valve for equalizing pressures across the device disclosed in U.S. Pat. No. 4,149,593.
U.S. Pat. No. 4,159,643 discloses a device similar to those mentioned above and has a relatively small flow capacity. This tool has lateral inlet ports which are closed by tensioning the conductor cable.
U.S. Pat. No. 4,373,583 discloses a test tool similar to those just discussed. It carries a self-contained recording pressure gage suspended from its lower end and therefore sends no well data to the surface during the testing of a well. This tool, therefore, may be run on a conventional wire line rather than a conductor line, since it requires no electrical energy for its operation. The present invention is an improvement over the invention of U.S. Pat. No. 4,373,583.
U.S. Pat. Re. No. 31,313 discloses a device similar to that of U.S. Pat. No. 4,373,583 in that it has lateral inlet ports which are opened and closed by moving a probe up or down through tensioning or relaxing the wire line or cable on which it is lowered into the well.
The MUST Drill Stem Test Tool of Flopetrol-Johnston disclosed in the brochure mentioned above and in the article published in WORLD OIL magazine provides a non-retrievable valve opened and closed from the surface by tensioning and relaxing the conductor cable connected to the probe-like tool latched into the valve. Even with the valve open and the well producing, no flow takes place through the probe. All flow moves outward through the side of the valve into a bypass passage which then empties back into the tubing at a location near but somewhat below the upper end of the probe. The device provides large or "unrestricted" flow capacity. The probe automatically releases when a predetermined number (up to twelve) of open-close cycles have been performed.
U.S. Pat. No. 2,698,056 which issued to S. J. E. Marshall et al. on Dec. 28, 1954; U.S. Pat. No. 2,920,704 which issued to John V. Fredd on Jan. 12, 1960; U.S. Pat. No. 2,673,614 issued to A. A. Miller on Mar. 30, 1954; and U.S. Pat. No. 3,208,531 issued to J. W. Tamplen on Sept. 28, 1965; disclose various devices for locking well tools in a well flow conductor.
U.S. Pat. No. 2,673,614 shows keys having one abrupt shoulder engageable with a corresponding abrupt shoulder in a well for locating or stopping a locking device in a well at the desired location in a landing receptacle for its locking dogs to be expanded into a lock recess of that receptacle. A selective system is disclosed wherein a series of similar but slightly different receptacles are placed in a tubing string. A locking device is then provided with a selected set of locator keys to cause the device to stop at a preselected receptacle.
U.S. Pat. No. 3,208,531 discloses a locking device which uses keys profiled similarly to the keys of U.S. Pat. No. 2,673,614 but performing both locating and locking functions.
The present invention is an improvement over that disclosed in U.S. Pat. No. 4,373,583 and overcomes some of the problems encountered in test tools which are for use in existing wells in that it requires but two trips into the well--one trip to install the test tool and to perform the tests, and a second trip to retrieve the test tool. Also, the sleeve valve is easier to move between open and closed positions since pressures acting thereon are balanced. Further, the test tool has high flow capacity and can be cycled between open and closed positions any number of times with little or no jarring.